Global
Deserts Outlook Launched on World Environment
Day
Algiers/London/Nairobi/Rioja,
5 June 2006 – The world’s deserts are facing dramatic
changes as a result of global climate change,
high water demands, tourism and salt contamination
of irrigated soils.
Desert margins and so called
‘sky islands’-mountain areas within deserts that
have been important for people, wildlife and water
supplies for millennia-are under particular threat.
Global and regional instability,
leading to more military training grounds, prisons
and refugee holding stations, may also be set
to modify the desert landscape the new report
by the United Nations Environment Programme (UNEP)
suggests.
“These intrusions import many
people into deserts, generate considerable income
and help upgrade infrastructure but have large
environmental footprints particularly with respect
to water. In an insecure and competitive world,
this kind of investment will continue, even grow,”
it says.
Not all the changes need necessarily be harmful.
Some may have clear benefits for indigenous people
and other desert residents, and even the wider
world.
Most deserts have sunlight and
temperature regimes that favour—possibly surprisingly--
sites for shrimp and fish farms in locations like
Arizona to the Negev desert in Israel.
Such ventures offer new and
potentially environmentally-friendly livelihoods
for local people and businesses.
Eventually these and other developments
that make use of the unique features of deserts
could also help relieve the pressure on mangroves
and sensitive coastlines which are currently being
cleared for shrimp ponds.
Meanwhile, animals and wild
plants, remarkably adapted to the harsh and often
unpredictable desert world, promise new sources
of drugs, industrial products and crops.
Nipa, a salt grass harvested
in the Sonoran desert of north western Mexico
at the delta of the Colorado River by the Cocopahs
people, thrives on pure seawater producing large
grain yields the size of wheat.
“It is a strong candidate for
a major global food crop and could become this
desert’s greatest gift to the world,” says the
report.
Meanwhile some experts believe deserts could become
the carbon-free power houses of the 21st century.
They argue that an area 800 by 800 km of a desert
such as the Sahara could capture enough solar
energy to generate all the world’s electricity
needs and more.
Many of the changes that deserts
could experience are likely to be far less positive
unless they are better controlled.
Population growth and inefficient
water use are, by 2050, set to move some countries
with deserts beyond thresholds of water stress,
or even worse, water scarcity. Examples include
Chad, Iraq, Niger and Syria.
Renewable supplies of water
which are fed to deserts by large rivers are also
expected to be threatened, in some cases severely,
by 2025.
Examples include the Gariep
River in southern Africa; the Rio Grande and Colorado
Rivers in North America; the Tigris and Euphrates
in southwestern Asia and the Amu Darya and Indus
Rivers in central Asia.
Better management of water supplies
will be the key challenge for the future of deserts
but could, if successful, be a beacon of hope
and good practice for other water-short parts
of the globe.
These are among the findings
of UNEP’s Global Deserts Outlook launched to mark
World Environment Day on 5 June.
The main World Environment Day celebrations for
2006 are being held in the Algerian capital Algiers
with the theme “Don’t Desert Drylands!”. 2006
is also the United Nations International Year
of Deserts and Desertification.
The Global Deserts Outlook is
the first thematic report in the Global Environment
Outlook (GEO) series of environmental assessments
by UNEP.
This GEO report, prepared by
experts from across the globe, traces the history
and astonishing biology of the deserts and assesses
likely future changes in deserts.
It also flags policy options
that may help governments and relevant bodies
deliver a more sustainable future for these extraordinary
regions.
Shafqat Kakakhel, UNEP’s Officer
in Charge and Deputy Executive Director, said:
“There are many popular and sometimes misplaced
views of deserts which this report either confirms
or overturns. Far from being barren wastelands,
they emerge as biologically, economically and
culturally dynamic while being increasingly subject
to the impacts and pressures of the modern world”.
“They also emerge as places
of new economic and livelihood possibilities underlining
yet again that the environment is not a luxury
but a key element in the fight against poverty
and the delivery of internationally-agreed development
goals such as the Millennium Development Goals,”
he added.
Mr Kakakhel cited the growing
interest in deserts as prime locations for aquaculture
and the source of novel drugs, herbal medicines
and industrial products derived from the plants
and animals adapted to these arid areas.
“If the huge, solar-power potential
of deserts can be economically harnessed the world
has a future free from fossil fuels. And tourism
based around desert nature can, if sensitively
managed, deliver new prospects and perspectives
for people in some of the poorest parts of the
world,” he added.
Some Key Facts from the Global
Deserts Outlook
Almost one-quarter of the earth’s
land surface – some 33.7 million square kilometres
– has been defined as “desert” in some sense.
These deserts are inhabited by over 500 million
people, significantly more than previously thought.
The desert cores remain pristine
in many parts of the world, representing some
of the planet’s last remaining areas of total
wilderness.
The desert fringes in many places,
however, suffer high pressures from human activities
and include several of the most threatened terrestrial
ecoregions of the world.
Climate Change
Water is a vital and limiting
factor in deserts. Many life forms exist in limbo,
suddenly bursting into fruit and reproducing in
vast numbers in response to ‘rain pulses’. Water
supply is also vital for human settlements and
these are even more vulnerable to unsustainable
withdrawals of water
Climate change as a result of
human-made emissions is already affecting deserts.
The overall temperature increase
of between 0.5 and two degrees C over the period
1976-2000 has been much higher than the average
global rise of 0.45 degrees C.
The Dashti Kbir desert in Iran
has seen a 16 per cent fall per decade in rainfall
during this same period; the Kalahari in South
Africa a 12 per cent decline and the Atacama desert
in Chile , an eight per cent drop.
In contrast Kizil Kum in Afghanistan
and the Western Desert in Egypt have seen an four
to eight per cent rise over the same period.
Profound changes with important
implications for water supplies and people, and
desert plants and animals, are likely in some
regions unless greenhouse gas emissions are dramatically
reduced.
Under scenarios developed by
the Intergovernmental Panel on Climate Change
(IPCC), the body of scientists advising governments
and the United Nations, temperatures in deserts
could rise by an average of as much as five to
seven degrees C by 2071 -2100, compared to the
average in the period 1961-11000.
Many deserts will see declines
in rainfall of between five and ten or even 15
per cent with deserts in southerly latitudes especially
vulnerable.
Most of the 12 desert regions,
whose future climate has been modeled, are facing
a drier future with rainfall in some cases forecast
to be 10 to 20 per cent lower by the end of the
century.
This applies to the Great Victoria
desert of Australia; the Atacama and also to the
northern-hemisphere deserts such as the Colorado
and Great Basin region in the United States.
Only the Gobi desert in China
is predicted to have rainfall increases of between
ten and 15 per cent.
The problem will almost certainly
be compounded by the melting of glaciers whose
waters sustain many deserts such as the Atacama
and Monte Deserts in South America.
The glaciers in the mountains
of High Asia may decline by between just over
40 per cent and 80 per cent by the end of the
century under two IPCC scenarios, says the report.
The situation is being aggravated
by overgrazing and the cutting of trees and other
vegetation in these desert mountain realms thus
reducing the capacity of these natural water towers.
The report adds: “A large fraction
of the water used for agricultural and domestic
purposes in the arid Southwest of the United States,
the deserts of Central Asia and the Atacama and
Puna Deserts on both sides of the Andes is drawn
from rivers that originate in glaciated/snow-covered
mountains”.
Modeling of the impact on California’s irrigated
farmlands indicates that they are likely “to lose
more than 15 per cent of their value because of
losses in snow pack,” says the Global Deserts
Outlook.
Other impacts of climate change
include the turning of some semi-arid rangelands
into deserts and the re-mobilization of dunes
currently stabilized by vegetation as in the southwestern
Kalahari Desert in southern Africa.
Wider Water Issues and Agriculture
Underground water supplies,
some centred around oases and in ‘sky islands’--formed
over thousands and in some cases over a million
years-- are increasingly being drained of water
for agriculture and settlements including retirement
resorts.
The biggest casualties may be
cities in the deserts of southwestern Asia and
in the southwest United States.
Other water supplies are under
threat from salinization and pollution by pesticides
and herbicides.
Rising water-tables beneath
irrigated soils has led and will probably lead
to much more salinization of soils as is already
occurring in western China, India, Pakistan, Iraq
and Australia. For example in the Tarim River
basin of China, more than 12,000 square km of
land has been salinized over the last 30 years
or so.
In some coastal areas ground-water supplies have
been contaminated as seawater invades subsurface
waters that have been over-exploited. Seawater
has penetrated 20km inland into some Libyan coastal
aquifers.
In some parts of the world,
deserts are becoming increasingly attractive as
places to live and to retire, but this often requires
large pumping and water transfers.
While traditional American cities
like Detroit and Chicago have seen population
falls since the 1950s, desert ones like Phoenix
and Tucson, Arizona, have seen populations rise
from almost zero to between 500,000 and 1.5 million
over the same period.
Countries like the United Arab
Emirates are also seeing a growth in retirees
which will certainly increase water demand.
Large rivers running through
deserts have supported desert people for millennia.
Many have been dammed, and although the dams store
valuable water, the water losses downstream have
led to serious impacts on floodplain and river
ecology.
The Colorado River in the southwestern
United States has been dammed to generate water
supplies and electricity for Arizona and California
but its delta in Mexico has lost most of its water
and productivity.
A similar story is linked with
the Aswan High Dam in Egypt. Built in 1970, it
has reduced the level of nutrient-rich silts and
soils flowing downstream causing the Nile Delta
to shrink.
One possibility to improve water efficiency is
to restrict irrigated agriculture to high value
crops like dates, intensive greenhouse farming
where evaporation is reduced and to aquaculture.
Low value crops like maize could be imported from
wetter parts of the world.
Desalination plants, which turn
sea water into drinking water, are used in some
counties like Saudi Arabia but they consume large
amounts of energy in a world where energy prices
are rising sharply.
More attention should be focused
on ancient and ingenious methods of water management
as they might offer sustainable options for the
future. These include underground channels known
as qanats and foggara in North Africa and karez
in countries like Pakistan.
Biodiversity
Urgent action is needed to protect
wildlife in deserts with hunting among the biggest
threats, says the report.
“Large convoys of air conditioned
caravans follow hunters across the deserts of
Arabia, Kazakhstan and Sudan,” it adds.
Desert species on the brink
of extinction or declining fast include various
species of gazelle, oryx, addax, Arabian tahr
and the Barbary sheep as well as one of the falconers
favourite prey, the Houbara.
Probable impacts include those
created by new roads, expanding settlements and
other infrastructure developments that concentrate
around desert montane areas.
“Sky islands” in deserts are
plant and animal communities that have been isolated
in mountain ranges when the deserts became rapidly
more arid some 20,000 years ago.
Many hold unique and rare species
that, like oceanic islands, have evolved in isolation.
These include the rich pine and oak forests of
the Moroccan Atlas Mountains; the Arabian tahr
goat found in the Al Hajar Mountains near the
Gulf of Oman and the wild olives and Saharan myrtles
of Niger’s Air Massif.
“At greatest risk are the few
patches of dry woodlands associated with desert
mountain habitats which may decline by up to 3.5
per cent per year,” adds the Global Deserts Outlook.
Indeed experts fear that these
woodlands—areas which made the great desert trades
such as the Silk Road, the cross-Sahara trade
and many others possible-- could be largely lost
in less than 50 years unless urgent action is
taken to protect and conserve them.
Desert wetlands, fed by the
large rivers crossing deserts, are probably the
most threatened ecosystem, as a result of their
valuable water supplies being diverted to domestic
or agricultural use. These include the extremely
threatened ecosystems of the Aral Sea and the
Mesopotamian Marshlands in Iraq.
The report estimates that desert
wilderness -- those areas where there are no nearby
roads, will decline from just under 60 per cent
of the current total desert area to just over
30 per cent by 2050.
“Species such as desert bighorn sheep, the Asian
Houbara bustard and California desert tortoise,
that are sensitive to fragmentation of habitat
or poaching, induced by increased access to areas
previously not accessible to people, will be affected
significantly by this change,” says the report.
New Industries from Aquaculture
to Tourism
Rising numbers of people are
attracted to deserts for hiking, fishing and to
view cultural artifacts.
Countries are recognizing this
and the number of desert-based conservation areas
including National Parks is set to climb.
Popular sites include Joshua
Tree National Park in North America, St Catherine’s
Monastery in Sinai and Uluru (Ayers Rock) in Australia.
A series of large transboundary
parks are being negotiated in southwestern Africa
which should offer new levels of protection to
the entire coastal Namib desert.
Some deserts areas—Arizona and
the Negev-- are capitalizing on the low costs
of land, mild winter temperatures and in some
cases the availability of ‘brackish’ water that
may be too salty for plant crops to farm crustaceans
and fish.
Raised in closed systems that
prevent evaporation, such farming can be more
water-efficient than crop production.
Micro algae called Haematococcus
that produce a reddish pigment are also being
grown in deserts, sometimes in long thin glass
tubes.
The pigment, an antioxidant,
is sold as a health product. It reputedly strengthens
the immune system, slows skin ageing and alleviates
muscle fatigue.
“The pharmaceutical potential
of desert plants has yet to be tapped,” says the
report.
Desert plants, from countries
like China and India, are being exported for herbal
treatments and medicines to places like Germany.
The report expects this trade will grow.
Meanwhile, scientists are also
screening desert plants for promising medicinal
compounds. Some, found in the Negev, are known
to hold anti-cancer and anti-malarial substances.
Others, from the deserts of
Argentina, Arizona and Morocco,are effective against
diseases like uterine cancer and infectious diseases.
Essential oils from two plants found in the deserts
of Morocco appear to enhance the growth and the
efficiency of feed conversion in poultry.
Compounds from Hoodia gordonii,
a dryland plant from the Kalahari Desert, are
being marketed as an appetite suppressant.
Notes to Editors
Order the report online from
Earthprint
Global Deserts Outlook has been
produced by UNEP’s Division of Early Warning and
Assessment and is the latest in its series of
Global Environment Outlooks http://www.grid.unep.ch/geo/
The full Global Deserts Outlook
will be available under embargo from 2 June and
on 5 June at www.unep.org and www.grida.no.
World Environment Day
is celebrated around the world annually on 5 June.
This year’s main host city is Algiers, Algeria.
Please go to http://www.unep.org/wed/2006/english/
where there are also other language versions of
the site and related materials.
